1. Field of the Invention
The present invention relates to a zoom lens system to be used in a compact video camera or digital camera and the like.
2. Description of the Related Art
Generally, in a zoom lens system, it is necessary to maintain a space to allow the lens groups to move for zooming, as a result, the overall length of the zoom lens system tends to be long in comparison with a fixed focus lens system. Accordingly, there is a physical limit in reducing the dimensions of a camera body measured in a direction parallel with the optical axis of a lens system of the camera (hereinafter, the thickness of a camera).
In recent years, development has been made to produce digital cameras with higher resolution, and accordingly a frame size (an image size determined by a lens system) of an image pick-up device, such as a CCD (charge-coupled device), has been increased, and an optical system as well tends to be larger. For Miniaturizing a camera with a zoom lens system, a retractable type camera which is arranged to retract the lens barrel thereof when the main power is turned off is known. However, the mechanism of this retractable type camera is complicated, and is disadvantageous in regard to costs.